I agree, I see the circuit the same way, the 6AS7 is the top of the super-mu (as it's also described by the designers in the beginning of the thread)... Sometimes I just can't find the proper words in English to describe what I mean. Describing technical stuff in a second language is not easy (for me), I knew it was not really correct when I wrote that the 6AS7 is in the final stage of the PS, and when I wrote it I expected that someone would ''correct me'' My point was, that it's not directly in the signal path doing signal amplification as in those headamps, I just could not find better words. Thanks for clarifying with a more proper description, links, references and all...

Morten, thanks for your work on the Tram2, I think you have inspired many owners to take the next steps.... I am currently waiting for a few parts before putting Rod Coleman heater supplies in place in order to remove the caps across the filaments....

...... In other uses I prefer 6080 over 6AS7, but unfortunately they are tricky to use in the Tram2 due to the size of the base on most 6080s.

That's interesting. Thanks Simon. May I ask you a couple of questions?

I have plenty of 6080's but found , like you that they just dont fit through the Tram2 top plate. Have you get any thoughts about the easiest way to enlarge the Tram2 6AS7 top plate opening to let the 6080 in?

Also since you understand the circuit and I dont do you think any 6AS7 type variants that have higher mu factors then the 6AS7/6080 mu=2 would be OK to try or are they going to push the circuit out of designed spec's?

That's interesting. Thanks Simon. May I ask you a couple of questions?

I have plenty of 6080's but found , like you that they just dont fit through the Tram2 top plate. Have you get any thoughts about the easiest way to enlarge the Tram2 6AS7 top plate opening to let the 6080 in?

Also since you understand the circuit and I dont do you think any 6AS7 type variants that have higher mu factors then the 6AS7/6080 mu=2 would be OK to try or are they going to push the circuit out of designed spec's?

As for using the near equivalent valves with a higher mu, I am not certain as I haven't really thought about it. Could be worth running a few sims to check it out. The brief look through the links I posted earlier seem to make me think it shouldn't be a huge problem, but it is whether any of the circuit needs a tweak to work with the change in tubes, and I cant answer that at the moment as I have not actually played around with the circuit.

Richard, I think your own diagnosis is correct: You have a dead DHT regulator board...

Hi all, so my brand new but faulty Tram2 went to the doctor and is currently undergoing surgery. Turns out that one of the CCS modules was dead and there were multiple earthing faults.

The earthing issues have been fixed, and the Coleman regulators have been installed.

While the amp is still in surgery and waiting for a replacement CCS kit (thanks Simon!), i decided to order some Duelund Alexanders for input caps, Mundorf Supremes for output caps, Audio Note tantalum resistors, and one of those Philips rectifer tubes.

In the meantime, a friend who had just installed Coleman regulators brought his Tram2 around for a few hours of listening -- this Tram2 is stuffed with premium parts, including wire. My goodness it sounded good! Just beautiful to listen to... and this is with brand new parts, not run-in at all, and also relatively cold.

So now i am even more excited and feeling very impatient to get mine running!!

Great to hear, that you are getting the preamp repaired Please remember to upgrade the cap + resistor on the Rod Coleman modules, it gives a nice improvement for little money and is so much easier to do before the modules are installed, than after...

Nice parts you are getting... The Duelund Alexander's has a slightly warmer and slightly less transparent sound compared to the more expensive models, but they still have the amazing natural sound that is the ''Duelund sound'', or maybe one should say lack of sound. It's one of those products that I'm proud of saying comes from our lille country

Nice with the other parts..! Personally I prefer the Shinkoh tantalium resistors over the AN, but all tantaliums are really nice... Also IMHO the Obbligato tinfoils are better than the Mundorf supremes for output caps, if you are talking about the standard Supremes that is? If you are going for the Supreme silver/gold/oil that is another story, but costly and takes up a lot of space since at least 12uF is needed...

Besides the Philips rectifier, what kind of tubes will you be using..!?

but costly and takes up a lot of space since at least 12uF is needed...

You only need 12uF if you retain the voltage divider network on the output, and have a SS power amp with low input impedance, as it appears to have been designed to work with loads down to about 10K.

Personally I have reasonably low sensitivity valve power amps with 100K input impedance, so I have replaced the voltage divider with a more regular 1M0 resistor, and the 12uF Obliggattos with 1uF Hovland output caps.